Lightning was the first commercial use of electricity. In 1879, Thomas Edison developed the first practical electric lamp. The incandescent lamp, as it is called, has proved to be immensely successful as it has found its way in hundreds of millions of homes across the world. However, because of its inherent inefficiency, the incandescent lamp is gradually being phased out in favor of compact fluorescent lamps (CFLs).
Today, there are a great variety of lamps with different underlying technologies and characteristics. Before giving their descriptions, we explain the meanings of a few terms that are used when comparing different types of lamps.

Lumen
Efficacy
Color temperature
Ballast
The lumen is a measure of the total light output of a lamp. For example, a typical 60 W incandescent lamp emits about 750 lumens whereas a 14 CFL has an output of 800 lumens.
The efficacy is a measure of how well the lamp converts electrical energy into light energy. Mathematically, it is the ratio of lumens output to power input. Thus, the efficacy of the incandescent lamp from the previous example is By comparison, the CFL has an efficacy of 800/14 = 57 lumens per watt. This means that the CFL produces 5 ( 57/12.5) times more light than the incandescent from the same amount of electricity.
The color temperature is a measure of the appearance of the light produced by a lamp. The color temperature is measured in degrees Kelvin (K). Lamps which have color temperatures of 3000 K and below emit “warm” light which is yellowish in colour. For example, incandescent lamps produce yellowish light and have a color temperature of about 2800 K. Lamps which have color temperatures of 4000 K and above emit a “cool” light which is somewhat bluish in color.
The ballast is an electronic component that regulates the amount of current fluorescent lamps and high intensity discharge lamps draw.

Rollover each lamp to have appropriate explanation